#!/usr/bin/perl

my $a = "a";
my $b = "b";
my $c = "c";
my $d = "d";
print "a=", a, ", b=", $b, ", c=", $c, ", d=", $d, "\n";
($a, $b, $c, $d) = ($d, $c, $b, $a);
print "a=", $a, ", b=", $b, ", c=", $c, ", d=", $d, "\n";

#Result:
#a=a, b=b, c=c, d=d
#a=d, b=c, c=b, d=a